Electrical protective device.



H. W BROWN. ELECTRICAL PROTECTIVE DEVICE. APPLICATION F1150 nic. 19. 191s.

1,168,054, `Patented Jan. 11, 1916.

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IlllIll WITNESSES: INVENTOR A@ AT'TORNEY UNTTED sTATEs PATENT oEEioE.

HAROLD W BROWN, OF ITHACA, NEW YORK, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRICAL PROTECTIVE DEVICE.

Specification of Letters`1atent.

PatentedJall. 11, 1916.

Application led December 19, 1913. Serial No. 807,709.

specification.

VMy invention relates to electrical protective devices and particularly to relays.

yThe object of my invention is to provide a. relay which has adjustable torque .characteristics.

The usual rotative type of relay has a. torque characteristic which is undesirable,

because, toward the end of the rotative' movement, additional work is imposed when contact is broken or made, and an additional torqlpe is required to do this additional wor lf a helical spring is attached to an arm of the rotatable member of a relay, thc spring will exert a series of different torques for different angular movements of the rotatable member. These torques, when plotted against their respective angular displacements, form curves which approach sine waves in shape. A lspring that is neither in compression nor tension when its crank is at right angles to the line of action of the spring has two complete cycles of torque revolution, and if the stationary point of attachment of the spring is at a considerable distance, and the crank is comparatively short, the curve which represents the stresses of the spring for its various positions is approximately a sine` curve. If,

however, the spring is in tension or in compression at all times during the rotation, there is only one cycle per revolution, and if the springtension is essentially unchanged the curve of its torque is ay sine curve having only one cycle per revolution. Usually springs lie between these two extremes so that if these two springs are applied to the same rotatable element, the resultant curve would be the combination of their respective single and double frequency curves. Since it is desirable to increase the force-tending to operate the contact members of aw relay toward the end of its rotationfthe force during the remainder of the rotation being approximately constant, and

since, by the proper combination and locaa tion of springs the. resultingtorque may be arm v12.

madeto conform to that which is desired, I provide an ordinary rotative type of relay with springs so arranged as to bring about the desired resultant torque curve. By properly advancing the phase. angle between the two springs, a curve showing a constant torque through a relatively long range may valso be secured.

Referring to the accompanying drawings, Figure 1 is a front elevational view of a relay embodying my invention; Fig. 2 is a fragmentary top view of the relay shown in Fig. 1, shown partially in section and partially in plan; Fig. 3 is a side view of a relay embodying my invention, shown partially in section and partially in elevation, and Fig. 4 is a diagrammatic view of a circuit protected by a relay `embodying my invention.

My invention comprises a case or. housing 1, magnetic structures 2 and 3, and a frame work 4. The frame work 4 supports an armature 5 and a controlling mechanism 6 comprising a pivotally mounted stop 7 having an indicator attached thereto, a scale 8, an actuating arm 9, a shaft 10, a gear wheel 11, a lever arm 12, springs 13 and 14, and a.

pivotally mounted indicator 15. The springs 13 and 14 are attached to the end of the lever arm 12 which is mounted on the shaft 10. The shaft 10 is operat'ed'by the gear wheel 11 through a pinion 16 on a main shaft 17 upon which is also mounted the armature 5. The spring 13 has its outer end attached to a stationary post 18, and the spring 14 has its outer end attached to the pivotally mounted indicator 15. Upon the magnetic structure 2 are located a main coil 19. andan auxiliary coil 20, and .upon the magnetic structure 3 are located the phase coils 21 which are connected in a local circuit 22 with the auxiliary coil 20. The actuating arm 9 operates a movable contact member 23 which makes contact with a. sta tionary contact member 24.

Referring now particularly to Fig. 4, my invention is used to protect a circuit 25 by tripping a circuit breaker-26 which is held in its closed position by an electromagnet 27 receiving current from a battery 28. The contact members 23 and 24 control the current that flows through the electro-v The member 23 is providedl magnet 27. Vwith a proiection 31 that is engaged by the he circuit breaker 261s released' by a spring 29 which operates a latch 30 when the electromagnet 27 is denergized.

The operation of my invention is similar to that of any of the well known types of relays, except that the torque is such that the opening of the circuit is madel with a decisive break due to a gradually increasing torque curve.

The operation of my invention as here shown, iS as follows: An overload upon the circuit 25 causes the coil 19 to take an excessive current that produces a magnetic ux in ythe magnetic structure 2. The flux thus produced induces a current in the coil 20 that is connected in series With the phase coils 21. Thus, the' armature 5 will rotate as a predetermined load because of the rotative field that is produced in the air gap. The time of operation may: be varied by limiting the part of a rotation the disk will have to make before the Contact is broken, and this may be done by moving the pivotally mounted stop 7 to the desired position, as indicated on thescale 8. The indicator 15, to which is attached one end of the spring 14, may be shifted to any desired po sition on the scale 8, thus altering the shape of the torque curve and,'consequently, the tripping current through certain ranges. When the arm 9, as shown in Fig. 2 or the arm 32 as shown in Fig. 4, comes into engagement with the projection 31 'from the movable Contact member 23, it causes the disengagement of the contact members 23 and 24, thus breaking the circuit through the tripping coil 27 of the circuit breaker 26 to permit it to interrupt the circuit 25, as hereinbefore described.

While I have illustrated a preferred form offmy invention, it will be understood that it may be variously modified with respect to the number ofand type of springs usedand with respect to other structural modi-l` tications without departing from the spirit and scope of the invention, as set'forth in the appended claims.

I claim as my invention:

1. In an electrical protective device, the combination with a rotatable member, of a plurality of springs angularly disposed with respect to each other and operatively connected to the rotatable member, and means for adjusting the relative tension of the said sprin 2. n an electrical rotective device, the combination with a re ay and a plurality of resilient means angularly disposed with respect to each other for controlling the shape of the torque curve of said protective device. I 3. In an electrical protective device, the

combination with a relay, of contact members, a plurality of resilient membersangularly disposed with respect to each other for controlling the shape of the torque curve of said protective device, and means for adjusting the angularity of said resilient members.

In an tlectrical protectivev device, the combination with a relay of the rotative type, of contact members operatedby said relay, resilient lmembers eccentrically connected to the rotatable member of the said relay. and means for varying the angular displacement of said resilient members with respect to each other.

5. The combination with an electro-responsive device, of a plurality of resilient means for retarding the movable member of the said electro-responsive device, said resilient .means being so disposed with respect to each other and to the movable member of the electro-responsive device that the movable member of the electro-'responsive device has a substantially constant torque during the first part of its movement and a relatively greater torque during the latter part of its movement;

6. In an electrical protective device, the combination with a relay of the rotative type, of means whereby said relay may actuate an auxiliary circuit, a plurality of springs eccentrically connected to the rotatable member of said relay, and means for adjusting the angular displacement of said springs with respect to eachother.

7. In an electrical protective device, the combination with a relay of the rotative type, a plurality of springs eccentrlcal'ly connected to the rotatable member of said relay and angularly displaced with respect to each other, and means for adjusting the relative tension on said springs.

8. A relay comprising a movable member, two resilient members operatively connected to the movable-member and means for adjusting the relative position of the said resilient members with respect to each other.

9. An electro-responsive device comprisingl an armature, two' springs operatively connected thereto and means for adjusting the relative tension of the said springs and their angular relation with respect to each other. l In testimony whereof, I have hereunto subscribed my name this 28th day of November, 1913.

HAROLD w. BROWN.

Witnesses:

VFRED L. CLARK, I). V. PRocToR.

Copies of .this patent may be obtained for ve cents each, by addressing the Commissioner ot Patents,

Washington, I2. C.

Corrections in Letters Patent No; 1,168,054.v

It is hereby certified that in Letters Patent No` 1,168,054, granted January 11, 1916, upon the application of Harold W. Brown, of Ithaca, New York, for an improvement in Electrical Protective Devices, errors appear in the printed speci- I cation requiring correction as follows: loge 1, line 32, after the word torque insert the word per; page 2, line 17, for the Word` ne read at; same page, line i 67, claim 4, for the word tleetri'cal read electrical; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the ease in the Patent Olice. I

Signed and sealed this 8th day of February, A. D., 1,916.

R. F. WHITEHEAD,

Acting Commissioner of Patents.

[SEAL] 

